Identify:

Adjectives are essential for describing nouns and pronouns. These key components let you describe people, animals, places, concepts, and things!

Study:

First let’s take another look at nouns. In both English and in French, nouns have number; that is, a noun can be either singular or plural. But, unlike English, all French nouns also have gender; any given French noun is either masculine or feminine.

Like French nouns, French adjectives(les adjectifs) also have number (singular or plural) and gender (masculine or feminine). In French, adjectives must agree in gender (masculine or feminine)AND number (singular or plural) with the nouns or pronouns they describe. This means that we must use the masculine singular form of an adjective to describe a masculine singular noun; we must use the feminine plural form of an adjective to describe a feminine plural noun, and so on.

Le film intéressant. (‘film’ is a masculine singular noun, and ‘intéressant’ reflects this)
The interesting film.

(g) The masculine adjectives beau, nouveau, and vieux change respectively to bel, nouvel, and vieil in front of a masculine singular noun that begins with a vowel or a silent letter ‘h’. The feminine form is derived by doubling the final ‘l’ of bel, nouvel, or vieil and adding -e :